/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.qpid.jms.util;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertTrue;

import java.util.ArrayList;
import java.util.List;

import org.junit.Test;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class LRUCacheTest {

    protected static final Logger LOG = LoggerFactory.getLogger(LRUCacheTest.class);

    @Test
    public void testLRUCache() {
        LRUCache<Long, Long> underTest = new LRUCache<Long, Long>();
        assertEquals(10000, underTest.getMaxCacheSize());
        underTest.setMaxCacheSize(1000);
        assertEquals(1000, underTest.getMaxCacheSize());
    }

    @Test
    public void testResize() throws Exception {
        LRUCache<Long, Long> underTest = new LRUCache<Long, Long>(1000);

        Long count = new Long(0);
        long max = 0;
        for (; count < 27276827; count++) {
            long start = System.currentTimeMillis();
            if (!underTest.containsKey(count)) {
                underTest.put(count, count);
            }
            long duration = System.currentTimeMillis() - start;
            if (duration > max) {
                LOG.info("count: " + count + ", new max=" + duration);
                max = duration;
            }
            if (count % 100000000 == 0) {
                LOG.info("count: " + count + ", max=" + max);
            }
        }
        assertEquals("size is still in order", 1000, underTest.size());
    }

    @SuppressWarnings("serial")
    @Test
    public void testOnCacheEviction() {

        final int ENTRY_COUNT = 20;

        List<CacheEntry> entries = new ArrayList<CacheEntry>();
        LRUCache<String, CacheEntry> cache = new LRUCache<String, CacheEntry>(ENTRY_COUNT / 2) {

            @Override
            protected void onCacheEviction(java.util.Map.Entry<String,CacheEntry> eldest) {
                eldest.getValue().close();
            };
        };

        for (int i = 0; i < ENTRY_COUNT; ++i) {
            CacheEntry entry = new CacheEntry();
            entries.add(entry);
            cache.put("Entry:" + i, entry);
        }

        for (int i = 0; i < ENTRY_COUNT; ++i) {
            if (i < ENTRY_COUNT / 2) {
                assertFalse(entries.get(i).isOpen());
            } else {
                assertTrue(entries.get(i).isOpen());
            }
        }
    }

    private static class CacheEntry {
        private boolean open = true;

        public void close() {
            this.open = false;
        }

        public boolean isOpen() {
            return open;
        }
    }
}